Method of forming hollow reenforced posts



Mrcl 3, 1931'. w. UMDERWOQD 1,794,503

METHOD FORMING HOLLOW REENFORCED POSTS Filed Dec. 14, i927A 2 sheetssheet 1 F57/ z/ l Uff. 4;/

//JI a .3 MW,

lw A 4| March 3, .1931. w. uNpERwooD METHOD 0F FORMINGv HOLLOW RENFORCED POSTS.

Filed Dec. v14. 1927 2 Sheets-Sheet 2 Patented Mar. ,3, 193i y cnr-nin sirerrs .PATENT ori-ics 'l WEs'rERN UNDERWOOD, oFzsAN're MONICA, cALirfo'nNrA, AAssiefivcn `To Le nUXj MANU- FACTURING COMPANY, 'or Los ANGELES, CALIFORNIA, ,A CORPORATION or CALI- FORNIA METHOD OFFGRMING HOLLOWJREENFORCED .POSTS Application filed December 14, 1927. Serial lN'o.'$159,914.

of cementitious 1nateria-l,require a metal reenforcing structure to, give them the necessary strength', and require a longitudinal passaoe or opeiiing'to raccominodate Wires or other parts. Posts of the character mentioned are 15 usually long, and yi'fherefore diiiiculty has been experienced incastingthem With-the necessary metallic reenforcements in the desired Position- T 0 Overcome the .difcillty Qf properlypositioning reenforceinents in cast 20 monolithic posts, and at the same time permit of u'singthe centrifugal method ,of casting, the reenforceinents have been put under tension or artificial strains within the molds. n This practice is not 'altogether desirable as ra. v M thetensioned or strained reenforceinent tends to return t'o its normal condition when released, and therefore tends v.to break its bond with the ceinentitious 1'body cast'around it. Further, in practice, `when following, the centrifugal method of casting, it is common to obtain i the desired longitudinal opening through the .casting by Partially fillingfthe mold,'arranging'it in a horizontal position and then depending upon centrifugal forcev to distribute ,the blastio `material in the mold and leave `an opening or void at tl'ie center. This LApractice leads to many diiiieulties,` for instance, .the equipnjient necessary toA handle alarge, long mold in ,ahorizongtal position androtate it at` the necessary-speed forthe centrifugal casting process, vinvolves' many mechanical complications, aiid-l-urther, the,

opening 'formed in the finished -productgbeing .5.5 dependent upon the proper illin-g'of the mold and the proper centrifugal casting action pis noltalways perfect.r I

it is .a general; object of -this invention -to providerainethod otforming oir castinga hoiioiv', `.ree-nf rce-d,. cement-itious' xpost stru-c'- reen-fore ture ivherebyth'e undesirablefeatures above referred toI areuelimnated or overcome. i

It is an object of this invention to provide anl eiiective', commercially,practical method ofiorinin g alviollo-KW, monolithicpost With a free or unstrained An'ietallic -reenforcement definitely positioiiedtherein.

lt a uitherrobject this invention to provide an rimproved method lothandling and operating afpost meld reen forcement and core to produce aholloiv, 'ree'niorcem monolithic post'in a simplefandpractical manner.`

Anothenohject theiinventionis toY provide method vofpacking or casting plastic material in post niold, or the like, whereby the materialis cast Without undesirable voids and with a uniform dense outer surface. n

The objects and i'eatures of the invention ivill'be understood from the tolloWii-igy detaileddescription of a typical manner of carrying it out,y throughout which description I refer to the accompanying drawings, in which:

F l is a longitudinal, detailed, sectional view Ot' a post mold` showing the reenii'orcenientiii place therein and showing the core beine' inverted? aview siinilaito Fig. l showing the coreset in place and showing the mold in i'erftical position A on 4a vibrating machine.;`

`Fig. Sis ,an ',eiilarge'd, detailed, sectional vieiv showing the manner in which oneend Oi the reen'torcement is guided in the mold; and

Fig. 4l is a View showing the mold inpesition in a machine voperatable to .rotatey certain parts being shown in section. My linveiition isintended primarily for the manufacture :of hollow, reentorcfed, ceinontitionl 'or monolithic posts,- such as `are used in lighting stz'indards or electroliers.fy This particular type otmonolithicstructure requ'i" een@ qualities/inthe nnisiiea pierna i hasgiven risetoserious larobleins.l For eirainplegthedesignand proportioning of the ordinary lighting postrequire a fairly hea'vv metallicreenforcing structure in the cementitious body, and further Arequire that vsuch ""rbe definitely vand accuratelypozthebody. `-**`i1.rtlier,` in order to sitioned iivobtaiiifthe 'deisiiled'stren-gth of the cementi-A tious body and the desired texture at the exterior of the body, it has been found advantageous to employ the centrifugal method in the casting of the body.

My invention provides primarily for the manufacture of a post of the character mentioned with the use of a sectional mold and core therefor, whereby the reenforcement for the post is definitely and freely held in position to be cast in the post, the filling of the mold with plastic material, for instance, a plastic cementitious mixture, and at the same time operatinglthe mold so that the material packed therein, operating the mold to equalize or uniformly packthe material in the mold, and then rotating the mold in a manner -similar to that followedkin the ordinary centrifugal casting process.

The mold used in carrying out my process may be a suitable sectional mold having a body 1G divided longitudinally into a plu- Cil raliy of sections, a cover plate 11 applied to the small or head end of the body, a mounting plate 12 to be applied over the cover 11 to facilitate mountingthe mold in suitable machines, a mounting plate 13 for application to the base or large end of the body over the reenforcement and core to close the mold and facilitate its being handled in suitable machines, and various other parts, the details and functions of which may be varied as conditions require. It is to be under stood, of course, that the body lOfof the mold is hollow or formed with an opening A, shaped and finished to give the post the desircd proportioning and exterior design. The ends of the :mold 10 vary, one being designed to .form the head end of the post, the other being designed to form the base end of the post. 'i

The reenforcement 1a to be embedded or cast inthe post, may be asimple, open, metal structure including a plurality of longitudinal rods 15, a spacer ring 16 for the rods, transverse ties 17 binding the rods together, and foot-*brackets 18 on the base ends of the rodsto be embodied in the base end of the post to have parts 19 projecting therefrom. The brackets 18 are adapted to be attached to the base end of the mold Whilethe head ends of the rods are adapted to extend freely into sockets 30 in the cover plate 11.

The core to be used in the mold and in conjunction with lthe reenforcement, may include an elongate bodyvQO to be arranged longitudinally through the space A of the inold body 10, and a mounting plate 21 on` the base end of the body 2O to be attached to the base end of the mold body 10.v The mold cover 11 and the head end of the core body 20 co-opera-te so that the head end of the core body is held in the desiredposition in the space A. In the construction shown, a projection 22 is provided on the inner rside of the cover 11 to extend-V into a socket 23 into the mold.

provided in the head end of the core body. It is to be noted that the core body is tapered longitudinally so that it can be withdrawn from the cast post through the base end of the mold. The mounting plate 21 is provided With one or moreopenings 24 to register-With `the opening A in the mold body 10 when the plate is applied to the mold body, as shown in Fig. 2. The openings 24 are provided to allow the plastic material to be filled The parts are related so that the plate 13 covers the openings 2a When applied to the mold.

In accordance with the method provided by my invention, the cover 11 is applied to the mold body 10, and the reenforcement 14 is positioned in the mold space A with the projecting parts 19 of the foot brackets 1S attached to the base end of the mold body 10, and the head ends of the rods 15 guided by the sockets 30 in the cover 11. The core is then inserted or arranged in place through the base end of the mold so that the head end of the core body is guided or held in position by the cover 11, and the plate 21 is attached to the base end of the mold body 10. When the core is inplace, it engages the spacer ring 16 of the reenforcement and thus spaces or guides the reenforcement in the space A.

The mold is now ready to be filled, and is arranged in a vertical position with its base end up. The desired plastic material, for instance, a suitable cementitious mixture, is then filled into the mold through the openings 24 andthe plate 21, and as the mold is filled, it is vibrated so that the plastic material is settled or packed in a manner to lill into all parts of the opening A and around all of the parts of the reenforcement. The vibration of the mold continues while the mold is being filled, and results in a complete filling of the mold Without voids or air pockets. The moldis preferably vibrated vertically. In Fig. 2 of the drawings, I have shown the mold mounted on a vibrating machine 35, Which includes a cam 36 operated by a shaft 37 to vibrate a vertically movable stem 38 carrying a platform 39 on Which the mold is supported. After the mold has been completely filled under the conditions just de- 'il scribed, the vibration is preferably continued for atime in order that all of the 1naterial in the mold be thoroughly settled or packed to substantially the same extent. In practice, I have found it desirable to continue the vibration of the mold for a period of about live minutes after the mold has been completely filled. Y

In the preferred carrying out of my invention, I then close the mold by means of the plate 13, and turn it end for end so that the base end is down, as shown in Fig. 4:. The mold is then spun or rapidly rotated about its longitudinal axis. This step of the process may be carried out in accordance with the lli) fili

the upper end of the mold.

general practice followed in'casting ceinentitions material centrifugally, the exact rate of rotation and the extent of rotation depending upon many factors, such as, the material being cast, the size and nature ofthe mold, the character of exterior desired on the cast product, etc. rl`he rotation Voffthe mold further packs or fills thef'plasticimaterial into the mold body so that the exterior of the post or finished product is sharply cast and is dense.

In Fig. e of the drawings, I disclose a machine such as may be used in rotating the mold. In this particular machine the mold is mounted in a vertical position through the .mounting plates l2 and 13. The machine includes a lower bearing platform rotatably simporting the lower end of the mold, and a top bearing 5l rotatably supporting The mold is rotated from a drive spindle 52 through the bearing 51, the desired speed of the spindle being obtained thro-ugh a belt drive 53 em bodied in the machine.

lVhen the post has been completely formed or cast as above described, it is allowed to stand in the mold a short time, say a few hours, until it hasV set sufficient to permit of the core being Withdrawn and the mold sections separated. In accordance Withprao tice followed in the manufacture of products of this kind, the post, after being removed from the mold, is preferably allowed to stand in Water until Well set, after Which its exterior is finished, for instance, acid etched, to give it the desired appearance.

From the foregoing description, it will be apparent that my present invention provides a process or method of maiiufacture which is simple and inexpensive, at the same Vtime capable of being carried out economically on a commercial scale.V Particular attention is called to the fact that the reenforcement is definitely and accurately held or guided in the mold space A Without being put under tension or strain. This is a very iniportant feature of the process, as it allows the reenforcement to set vin the cementitious body under natural or normal conditions, thus assuring a proper and permanent bond between the reenforcing members and the cast body. Further, it is to be noted that the method of operating the mold and handling it results in a uniform and equalized packing of the material in the mold so that the finished post is without air pockets or voids and of substantially uniform density throughout its length. It also is to be noted that my invenv tion provides for the manufacture of apost having all of the desirable characteristics of a manufactured by the centrifualcasting method andk at the same time eliminates the complications and undesirable features that have heretofore attended the centrifugal method.

'av'ing described i'nyinvention 'I vclaimz' l: 1 ,method ,ofpacking vplastic materia-l into: mold foflthe character-described "i115k cluding fillingtlie *material intothe mold with ai@ maia; iii? averties-:i position and vibra-figg. t ie' the vmold While it Iis lbeing filled, turning mold end for .endand` th en rotating it.

2. The methodof packing-plastic material into a mold of the character described including filling the material into the mold with the mold in a vertical position and vibrating the mold vertically as it is being filled, continuing the vibration of the mold after it is filled, then turning the iilled mold over end for end, and then rotating the mold.

3. The method of casting a ceinentitious post with a metal reenforcement including placing the reenforcement in a mold to be free to expand or contract longitudinally of the mold and to be definitely positioned laterally in the mold, filling the mold With plastic ceinentitious material and then rotating the mold. i

4. The method of casting a cementitious post with a metal reenforcement including placing thev reenforcement in a mold to be free to expand or contract longitudinally of the mold and to be definitely positioned laterally in the mold, filling the mold with plastic cementitious material, vibrating the mold While it is being filled, and then rotating the filled mold.

5. The method of casting. a cementitious post With a metal reenforcement including placing the reenforceinent in a mold, With one end attached to one end of the' mold and the other end guided aga-inst lateral 1nove` ment'by the other end of the mold to be free longitudinally of the mold, packing plastic cementitious material in the mold, and then rotating the full mold. f

6. The method of casting as cementitious post With ainetal reenforcement `including placing the reenforceinent in a mold definitely spaced' at both its ends from a core ink the mold and free to expand or contract longitudinally, packing plastic cementitious material'in the mold, and then rotating the filled mold.

7. The method of casting a cementitious post with a metal reenforcement including placing the reenforcement in a mold, spaced in the mold from a core and having one end attached to one end of the mold, and the other end guided by the other end of the mold to be free longitudinally of the mold, filling plastic cementitious material into the mold with the mold in a vertical position, vibrating the mold an prete-nea s lli) Y vertically While it is beng filled, continuing the vibration of the mold after it is lled, then turning the mold over end for end, and then rotating theV mold about its central longitudinal axis. Y

8. The method of packing plastic material into a mold of the character described including fllling the materiel into the mold with the mold in e vertical position and Vvibrating the mold vertically While it is being filled, turning the mold end for end, and then rotating it.

In Witness that I claim the foregoing I have hereunto subscribed my name this 6th day of December, 1927.

Y WESTERN UNDERWOOD. 

